The present invention relates to a mechanism for adjusting the circumferential position of a printing cylinder.
There are many known mechanisms for adjusting the circumferential position of a printing cylinder. Typically, such circumferential adjustment mechanisms include a sliding helical gear which meshes with another helical gear, and upon relative axial sliding movement between the gears, the printing cylinder is rotated for purposes of circumferential register adjustment of the cylinder. Many such designs are somewhat complicated due to the fact that when the cylinder is moved axially for side adjustment of the cylinder, one of the helical gears moves relative to the other helical gear, and thus axial adjustment of the cylinder could destroy the circumferential register of the cylinder, unless compensation is provided. Many efforts have been made in order to compensate for the undesired circumferential change in cylinder adjustment which occurs upon such axial movement of the cylinder. Frequently, compound gearing has been utilized to compensate for the circumferential change upon axial movement of the cylinder, and U.S. Pat. No. 3,717,092 discloses a known manner of solving the problem to which the present invention is directed.
U.S. Pat. No. 3,630,145 discloses another approach to the solution of the above noted problem, however, the complexity and non-coaxial arrangement of the gearing is a substantial disadvantage to such a design.